1. Field of the Invention
This invention relates generally to reinforced hose, more particularly to a flame resistant hose construction, and specifically a rubber hose reinforced with fiberglass cord fabric.
2. Description of the Prior Art
Conventional hoses with rubber layers and spiraled or braided textile reinforcements of fibers such as polyester and nylon lose their performance in the presence of a heat source at temperatures above 150° C. or when exposed to open flames. One approach to increasing the heat or flame resistance of a hose is to include insulating layers between the reinforcement layers and the heat source. An example of this approach is taught in U.S. Pat. No. 3,223,565 to Fritz et al. Fritz et al. introduce two intermediate heat insulating layers of fiberglass cord fabric between the braided polyester reinforcing layer and the inner lining of silicone elastomer. The resulting hose is said to convey hot air heated to 615° F. (324° C.).
Another example of the same approach is taught in U.S. Pat. Pub. No. 2006/0151043A1 to Nanney et al. Nanney et al. teach adding an integral outer fire-sleeve layer of silicone, which could be reinforced with fiberglass, surrounding the metal reinforcement layers, along with a high-melting thermoplastic layer such as polyimide for thermal insulation between the metal reinforcement and the core tube. The hose is said to fail in the range of 400-500 seconds in fire testing according to SAE AS1055.
Conventional marine hoses used in a fuel system must be fire resistant to at least 2½ minutes, as specified in the marine fuel hose Standard BS EN ISO 7840. What is needed is a hose assembly with superior fire resisting qualities as specified in marine hose standard BS ISO 15540. What is needed is a hose assembly that can withstand fire testing at 800±50° C. flame temperatures for 30 minutes, followed by pressure proof testing at ambient temperature for two minutes.